The present invention relates to chromatography columns used in separating constituents of chemical and biological samples; and more particularly to such apparatus in which sample material is drawn through the column by centrifugal force or vacuum.
Tubular columns containing a separation medium, such as a filtration matrix or an ion exchange material among other media, are frequently utilized in the biotechnology field to separate constituent materials from a sample. For example, this technique is used to separate DNA, which passes through the column, from lower molecular weight substances, which are retained in the separation medium. The particular material of the separation medium is selected to separate a specific constituent. One version of such a process is referred to as "spun-column chromatography" as the column is spun in a centrifuge so that the centrifugal force drives the sample through the separation medium. The constituents that pass completely through the column can be collected for further processing or analysis. The procedure may be repeated with wash or eluant steps to remove and collect the constituents contained in the separation medium.
Previous assemblies for spun column chromatography included a filter tube that contained a resin filtration matrix. This filter tube has an open first end through which the sample to be separated is introduced and through which solvents and reagents may be added at different steps of the process. A second open end of the filter tube fits into a centrifuging tube which has only one open end for receiving the filter tube and which serves as a collection vessel for constituents that pass through the filter tube. The assembled tubes are placed into a fixed angle or a swinging bucket holder at an end of a centrifuge rotor arm. After centrifuging, the tubes are separated and different sample constituents are contained in each one.
A laboratory often has a large number of different chemical or biological samples to be processed in this manner. However, handling individual tube assemblies for each sample is laborious and time consuming. Therefore, it is desirable to have a separation column apparatus that can facilitate the simultaneous processing of multiple samples.
Another previous technique for drawing the sample through the column created a vacuum at the second end of the column tube. This process requires a different collection vessel into which the column tube is placed wherein a vacuum source can be connected to the vessel in a manner that does not interfere with the collection of sample constituents that pass through the column. These vacuum devices typically had a single column. Other vacuum devices, such as that disclosed in U.S. Pat. No. 4,775,629, could process several column tubes at one time, but the material passing through the column was carried out of the device by the vacuum and could not be collected.